Gregory J. Nixon, OD
Gregory J. Nixon, OD, is the associate dean for clinical services and clinical professor at The Ohio State University College of Optometry, Columbus, and a fellow of the American Academy of Optometry (FAAC). Optometry.OSU.edu
Glaucoma, the second-leading cause of blindness after cataracts, affects about three million Americans. But unlike cataracts, which can be corrected with surgery, damage from glaucoma can’t be reversed. Protecting your vision depends on three key factors, says Gregory J. Nixon, OD, FAAO—early detection, consistent treatment and monitoring.
If you have been diagnosed with glaucoma or are at risk for it, here’s what you need to know now…
Glaucoma is a progressive disease that damages the optic nerve that relays information from your retina to your brain. Glaucoma compromises the nerve fibers in your eye, causing you to lose peripheral vision and then eventually central vision. Problem: There are no early warning signs—glaucoma is largely asymptomatic yet insidiously progressive. The vision loss it causes is so slow that it’s difficult to notice on your own. In fact, by the time you realize that your vision has been compromised, up to 40% of your nerve fibers may be damaged. That is why annual eye exams (see page 22) are so important—simple tests done as part of a comprehensive eye exam can spot the earliest signs of glaucoma when there’s time to prevent or slow the progression. While there are many treatment options today, they aren’t helpful if glaucoma goes undetected.
The optic nerve damage caused by glaucoma usually is secondary to the eye’s higher-than-normal intraocular pressure (IOP). This ocular hypertension is typically caused when the fluid called aqueous humor in the front of the eye doesn’t drain properly. As the fluid buildup causes increased pressure, nerve fibers are damaged. Improving drainage and lowering IOP helps to slow glaucoma damage. Here are some treatment options…
Eyedrops. The most common glaucoma treatment is a range of medications available as prescription eyedrops. Problem: About two-thirds of patients don’t stick to their treatment plan. Common reasons include side effects, such as redness of the eyes…and failing to administer the eyedrops regularly—in the past, this might have been necessary up to four times a day. One of the most helpful advances in recent years has been the development of glaucoma medications that require just one daily dose. Now there is also an eyedrop formula that combines two very effective glaucoma drugs—latanoprost and netarsudil—that can be administered just once a day.
Medication implants. These small, surgically inserted devices deliver some of the same medications found in eyedrops in a timed-release fashion. The most recently approved implant delivers the drug travoprost, and 80% of patients who received the implant maintained normal IOP without patient-administered eyedrops for up to a year. Talk to your doctor about the choices available—some implants are approved for one-time-only use, whereas others can be replaced when they lose effectiveness.
Laser surgery. Laser procedures have long been used to reduce IOP by altering the eye’s trabecular meshwork, the spongy tissue that is a main pathway for draining fluid. Until recently, the most common laser surgery for glaucoma—selective laser trabeculoplasty (SLT)—had been offered only when eyedrops were not effective. But SLT now is available as a first-line therapy. It is a non-invasive office procedure, and its effects last a number of years and can be repeated. A new version of the laser used for glaucoma was FDA-approved at the end of 2023 and is the first to automatically define the optimal target location via a non-contact approach.
Incisional surgery. Another approach to improve the outflow of fluid is by surgically altering the drainage structures of the eye. This can be done with trabeculectomy surgery or by implanting a shunt, or drainage implant, in the eye. But these procedures carry significant risk for complications such as infections, scarring and hypotony, an unexpected dangerously low pressure that can also cause permanent vision loss. Therefore these procedures are reserved for the most advanced glaucoma cases when all other treatment options have been exhausted.
Minimally invasive or micro-invasive glaucoma surgery (MIGS). MIGS procedures have an improved safety profile over incisional surgery because they avoid major alterations to the ocular anatomy. While the drop in IOP may be less than can be achieved with incisional surgery, MIGS may reduce or even eliminate the need for topical therapy. MIGS is now a common companion procedure to cataract surgery because it can be done through the same incision used to remove the cataract.
Important: None of the treatments above are a cure—all they do is help lower IOP. Even if your eye pressure is brought into a normal range, the optic nerve damage can continue. The goal of glaucoma treatment isn’t only to lower IOP but also to ensure the health of the optic nerve and the visual field.
Getting a yearly comprehensive exam and, when indicated, checkups every three to four months to test eye pressure and the health of the optic nerve is essential to monitor glaucoma. Studies also have shown that self-monitoring between appointments can be particularly beneficial, potentially allowing you to increase the length of time between those visits and helping inform treatment.
Peak IOP most likely occurs while you’re asleep. Home monitoring allows you to measure pressure as soon as you wake up, which is most representative of your highest IOP. A recent innovation makes this easy to do—the handheld device iCare HOME tonometer. Prescribed by your doctor, you rent or buy this device, then hold it up to your eyes and take roughly four daily measurements over the course of two weeks. Your doctor can review the readings to get the most accurate average IOP.
The number-one risk factor for glaucoma is age—glaucoma predominantly impacts adults starting at age 40 and risk increases with each decade. But there are some risk factors that can be modified. We now know that having diabetes increases risk for glaucoma. There also is evidence of a link between high cholesterol and increased IOP. Taking steps to avoid or better manage these conditions can help.
High blood pressure itself is not a primary risk factor for glaucoma, but treatment for it can be if it causes nocturnal hypotension, when blood pressure dips to an unfavorably low level while you sleep. This low blood pressure that occurs while you sleep, when your IOP is the highest, can decrease blood flow to the optic nerve causing further damage. Nocturnal hypotension can cause or worsen glaucoma. That’s why blood pressure medication should be taken upon awakening, never at bedtime. Anyone with high blood pressure and/or diabetes should be even more vigilant about getting a yearly comprehensive eye exam to spot signs of glaucoma as early as possible.
Lifestyle modifications that are good for overall health also help reduce risk for glaucoma, aerobic exercise in particular. That’s because of its positive effects on blood vessels, including those in the eye. Aim for 30 minutes or more of brisk walking or running outside or on a treadmill at least four times a week.
